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Purpose: Computer-based applications became a popular option for auditory training, but their efficacy can be compromised by lack of users' compliance. Serious games are a new emerging field that promotes the use of games for purposes other than entertainment. The purpose of this clinical focus article was to describe the design and development of a new serious game-based auditory training application that aims at enhancing perceptual learning of speech in cochlear implant (CI) recipients. Method: Using a participatory action research protocol, three phases were used in the process of development of this application to ensure its appropriateness for the target population. There were eight participants in Phase I, 16 participants in Phase II, and 51 participants in Phase III. In Phase III, participants were required to provide feedback using an online questionnaire after a 1-week trial period. Results: Participants' feedback and reflection from each phase were used to enhance the design and functionality of the final application. Results from Phase III demonstrated that greater than 90% of participants in both groups rated their satisfaction with several features of the games 4 or more on a 5-point Likert scale, with 1 being very dissatisfied and 5 being very satisfied . Differences in mean ratings for some features were significantly different between the two groups, perhaps reflecting differences in their auditory abilities. Conclusion: Results demonstrated that participants were highly satisfied with several features of the application, suggesting its potential to offer CI users a unique training opportunity by presenting repetitive and structured listening exercises using serious games.

Although it is surgically more challenging, patients with bilateral temporal bone fractures (TBFs) are potential candidates for successful bilateral cochlear implantation (CI). This study aimed to investigate the feasibility of bilateral implantation in patients with sustained bilateral TBFs.Retrospective database study.Seven patients with bilateral cochlear implants who were diagnosed with TBFs were included in this study. Preoperative radiological and audiological evaluations were performed. The outcomes of the CI were also investigated.Hearing levels were restored to the mild-moderate range (40 dB) for nearly all patients and they reported an improved quality of life.CI in patients with TBF is safe and offers a solution for the restoration of hearing in a population who may experience sudden bilateral deafness. However, preoperative confirmation of intact auditory nerves and patent cochlea is essential to maximize the success of CI in this population.4 Laryngoscope, 132:2050-2055, 2022.

Background Speech audiometry materials are widely available in many different languages. However, there are no known standardized materials for the assessment of speech recognition in Arabic-speaking children. Purpose The aim of the study was to develop and validate phonetically balanced and psychometrically equivalent monosyllabic word recognition lists for children through a picture identification task. Research Design A prospective repeated-measure design was used. Monosyllabic words were chosen from children's storybooks and were evaluated for familiarity. The selected words were then divided into four phonetically balanced word lists. The final lists were evaluated for homogeneity and equivalency. Study Sample Ten adults and 32 children with normal hearing sensitivity were recruited. Data Collection and Analyses Lists were presented to adult subjects in 5 dB increment from 0 to 60 dB hearing level. Individual data were then fitted using a sigmoid function from which the 50% threshold, slopes at the 50% points, and slopes at the 20 to 80% points were derived to determine list psychometric properties. Lists were next presented to children in two separate sessions to assess their equivalency, validity, and reliability. Data were subjected to a mixed design analysis of variance. Results No statistically significant difference was found among the word lists. Conclusion This study provided an evidence that the monosyllabic word lists had comparable psychometric characteristics and reliability. This supports that the constructed speech corpus is a valid tool that can be used in assessing speech recognition in Arabic-speaking children.

To examine the construct, discriminative, and predictive validity, and the test-retest reliability of the Arabic Meaningful Use of Speech Scale (MUSS).Parents of 102 children with cochlear implantation (CI) with a matching control group of 102 children with normal hearing completed the Arabic-MUSS scale. A random subsample of 30 parents was interviewed after two weeks to examine the test-retest reliability.the construct validity of the Arabic-MUSS was established by exploratory factor analysis that yielded a unidimensional scale and explained a total of 92.48% of the variance in the total score of the Arabic-MUSS. The internal consistency of the scale was excellent with Cronbach's alpha = 0.975. The Arabic-MUSS discriminative validity was supported by the significant difference between the total score of children with CI and children with normal hearing (The Arabic-MUSS is a valid and reliable measure that can be used to guide plans for auditory rehabilitation and monitor the progress of children with cochlear implantation over time.IMPLICATIONS FOR REHABILITATIONThe Arabic-Meaningful Use of Speech Scale is a valid and reliable parent-report assessment.The Arabic-Meaningful Use of Speech Scale evaluates functional speech in children with cochlear implantation.Clinicians can use the Arabic- Meaningful Use of Speech Scale to plan and monitor the progress of auditory rehabilitation programs.

The main objectives of this study were to translate and adapt the infant-toddler meaningful integration scale (IT-MAIS) into Arabic and to establish the psychometric properties of the translated scale in children with a cochlear implant.The translation and cross-cultural adaptation of this questionnaire were completed in multiple steps and following standard translation protocols. In total, twenty-eight parents of young cochlear implant recipients completed IT-MAIS. Data were collected postoperatively and at 3-, 6-, 9-, and 12-month post-device activation. Data were examined for the validity and reliability of the scale. The internal consistency and reliability of the scale were analyzed using CronbachFindings demonstrated that the scale exhibited good face and content validity, suggesting that the scale is a one-dimensional measure. Additionally, the reliability analysis for the scale indicated high reliability and correlation among test items. IT-MAIS scores consistently improved over time for all participants and this improvement. correlated negatively with the duration of deafness.Current findings indicated that the translated Arabic version of the IT-MAIS scale could serve as a valid instrument for assessing the development of auditory skills in Arabic-speaking children with cochlear implants.

It is generally believed that the efficacy of cochlear implants is partly dependent on the condition of the stimulated neural population. Cochlear pathology is likely to affect the manner in which neurons respond to electrical stimulation, potentially resulting in differences in perception of electrical stimuli across cochlear implant recipients and across the electrode array in individual cochlear implant users. Several psychophysical and electrophysiological measures have been shown to predict cochlear health in animals and were used to assess conditions near individual stimulation sites in humans. In this study we examined the relationship between psychophysical strength-duration functions and spiral ganglion neuron density in two groups of guinea pigs with cochlear implants who had minimally-overlapping cochlear health profiles. One group was implanted in a hearing ear (N = 10) and the other group was deafened by cochlear perfusion of neomycin, inoculated with an adeno-associated viral vector with an Ntf3-gene insert (AAV.Ntf3) and implanted (N = 14). Psychophysically measured strength-duration functions for both monopolar and tripolar electrode configurations were then compared for the two treatment groups. Results were also compared to their histological outcomes. Overall, there were considerable differences between the two treatment groups in terms of their psychophysical performance as well as the relation between their functional performance and histological data. Animals in the neomycin-deafened, neurotrophin-treated, and implanted group (NNI) exhibited steeper strength-duration function slopes; slopes were positively correlated with SGN density (steeper slopes in animals that had higher SGN densities). In comparison, the implanted hearing (IH) group had shallower slopes and there was no relation between slopes and spiral ganglion density. Across all animals, slopes were negatively correlated with ensemble spontaneous activity levels (shallower slopes with higher ensemble spontaneous activity levels). We hypothesize that differences in strength-duration function slopes between the two treatment groups were related to the condition of the inner hair cells, which generate spontaneous activity that could affect the across-fiber synchrony and/or the size of the population of neural elements responding to electrical stimulation. In addition, it is likely that spiral ganglion neuron peripheral processes were present in the IH group, which could affect membrane properties of the stimulated neurons. Results suggest that the two treatment groups exhibited distinct patterns of variation in conditions near the stimulating electrodes that altered detection thresholds. Overall, the results of this study suggest a complex relationship between psychophysical detection thresholds for cochlear implant stimulation and nerve survival in the implanted cochlea. This relationship seems to depend on the characteristics of the electrical stimulus, the electrode configuration, and other biological features of the implanted cochlea such as the condition of the inner hair cells and the peripheral processes.

OBJECTIVE/HYPOTHESIS The aim of this study was to investigate cochlear implantation (CI) outcome in children with nerve deficiency. STUDY DESIGN Retrospective chart review. METHODS A total of seven children with prelingual profound deficiency (hypoplasia or aplasia) were included. A control group of 10 CI children with no cochlear nerve anomalies was also included. In addition to implant stimulation levels, children's performance on pure-tone audiometry, speech reception measure, and auditory and speech skills ratings were compared across groups. Additionally, pre- and postoperative audiologic results were evaluated for the group with nerve deficiency. RESULTS In general, children with nerve deficiency performed poorer than those without nerve deficiency on all tested measures. Stimulation levels were considerably higher and more variable than the control group. Results further showed that performance was dependent on the diameter of the internal auditory canal. CONCLUSION Overall, cochlear implantation outcome in children with auditory nerve deficiency is poorer and extremely more variable than those without nerve deficiency. However, three of the patients had a noticeable improvement in auditory performance postimplantation suggesting that CI is a viable option in this population but expected benefit can be dependent on the status of the cochlear nerve.

BackgroundCognitive abilities like language, memory, reasoning, visualization, and perceptual functioning shape human action and are considered critical to the successful interaction with the environment. Alternatively, hearing loss can disrupt a child’s ability to communicate, and negatively impact cognitive development. Cochlear implants (CI) restore auditory input thereby supporting communication and may enhance cognitive performance. This study compares general cognitive development after cochlear implantation (2017–2019) in two groups of Jordanian children implanted earlier (age:4–6 years,N = 22) and later (7–9 years,N = 16) to the development of randomly selected normal hearing peers (N = 48).DesignVisualization, reasoning, memory, and attention were assessed using the Leiter-R scale at baseline (before implantation), 8 months and 16 months post implantation for children with hearing loss. Same times of testing (baseline, 8 months and 16 months) were used for normal hearing peers.ResultsOver the 16-month period, the cognitive improvement of 4–6-year-old deaf children was greater than that of their normal hearing peers on the scales of visualization (5.62 vs. 4.40), reasoning (2.53 vs. 2.38) and memory (17.19 vs. 11.67). while the improvement of 7–9-year-old was less major than that of their normal hearing peers on all scales.ConclusionsThese results suggest that CI not only enhances communication skills but may improve cognitive functioning in deaf children. However, the extent of this improvement was dependent on age at intervention; current results demonstrated that the children received CI at young ages had better cognitive improvements.

One of the concerns during the cochlear implant candidacy process is the presence of chronic otitis media which could delay the implantation process. The aim of this study was to evaluate the surgical difficulties and the long-term complications in children with otitis media and to examine whether it is necessary to delay the implantation until the infection is resolved. The study used a comparative retrospective design based on chart review of all patients who received their implant(s) from January to December of 2012. A total of 200 patients were identified and were followed for 4 years post surgery. Patients were divided into three groups based on their history of otitis media (non-otitis media, chronic otitis media with effusion, and acute otitis media). Data included long-term complications, operative time and duration from first clinical visit to the time until implantation was received. None of study participants had long-term complications during the study period. The operative time was longer in the acute otitis media group with a difference of 45 min. The average delay in cochlear implantation due to the presence of otitis media in chronic group was more than 5 months. Pediatric patients with otitis media could be implanted in one stage safely and effectively.

BACKGROUND: Minimal access surgery has been promoted to reduce the surgical duration and complications of cochlear implant (CI) surgery. A requirement of minimal access surgery is adequate visualization of the surgical cavities. OBJECTIVE: The aim of this study was to evaluate whether a new light-integrated surgical retractor reduced CI surgical time. DESIGN: A retrospective comparative study. SETTING: Tertiary referral otolaryngology clinic. PATIENTS AND METHODS: We reviewed the records of all patients who received implants between January 2013 to May 2014 at King Abdul-Aziz University Hospital before and after use of the illuminated retractor. MAIN OUTCOME MEASURE(S): Duration of surgery before and after the use of the illuminated retractor. RESULTS: There were no statistically significant differences in the surgical duration of CI relating to use of the illuminated retractor in 117 patients. The mean (SD) surgery duration in the unilateral cases was 132.7 (45.5) minutes before and 125.32 (42.76) minutes after use of the illuminated retractor (P=.479). For the bilateral cases, the mean (SD) surgical time was 213.6 (45.7) minutes before and 206.5 (45.5) minutes after use of the retractor (P=.702). There were no adverse events with use of the new tool. CONCLUSION: The similar duration and lack of adverse events suggest that the illuminated retractor is safe to use when drilling the bony recess for the receiver-stimulator package within the subperiosteal pocket. LIMITATIONS: The method used to calculate surgical duration may explain why no reduction in duration was shown.

Purpose The aim of the current study was to review all pediatric cases with congenital deafness who underwent bilateral implantation in our center. Specifically, auditory performance and speech intelligibility ratings were compared across children based on their mode of bilateral stimulation (simultaneous or sequential implantation). Method A retrospective chart review design was used in this study. A total of 46 congenitally deaf children were included. Children ranged in age between 2 and 8 years, with a mean of 3 years 7 months. Participants were divided into 2 groups: those who received their bilateral implant simultaneously and those who received them sequentially. Categories of Auditory Performance (CAP; Archbold, Lutman, & Marshall, 1995 ) scores and Speech Intelligibility Rating (SIR; M. C. Allen, Nikolopoulos, & O'Donoghue, 1998 ) scores were used to measure their performance. Results Children scored an average of 4.1 (±1.6) on the CAP Scale and 1.6 (±1) on the SIR Scale. Results showed that children who received their implants simultaneously scored relatively higher on the CAP Scale than those with sequential implants. However, there were no differences between the 2 groups in SIR scores. These 2 outcome measures were not correlated with age at implantation. Conclusion The current study demonstrated that simultaneous implantation could potentially improve audiologic outcome.

Amazing progress has been made in providing useful hearing to hearing-impaired individuals using cochlear implants, but challenges remain. One such challenge is understanding the effects of partial degeneration of the auditory nerve, the target of cochlear implant stimulation. Here we review studies from our human and animal laboratories aimed at characterizing the health of the implanted cochlea and the auditory nerve. We use the data on cochlear and neural health to guide rehabilitation strategies. The data also motivate the development of tissue-engineering procedures to preserve or build a healthy cochlea and improve performance obtained by cochlear implant recipients or eventually replace the need for a cochlear implant. This article is part of a Special Issue entitledLasker Award.

To develop and validate a digitally recorded speech test battery to assess speech perception in Jordanian Arabic-speaking adults.Selected stimuli were digitally recorded and were divided into four lists of 25 words each. Speech audiometry was completed for all listeners. Participants were divided into two equal groups of 30 listeners each with equal male to female ratio. The first group of participants completed speech reception thresholds (SRTs) and word recognition testing on each of the four lists using a fixed intensity. The second group of listeners was tested on each of the four lists at different intensity levels in order to obtain the performance-intensity function.Sixty normal-hearing listeners in the age range of 19-25 years. All participants were native speakers of Jordanian Arabic.Results revealed that there were no significant differences between SRTs and pure tone average. Additionally, there were no differences across lists at multiple intensity levels.In general, the current study was successful in producing recorded speech materials for Jordanian Arabic population. This suggests that the speech stimuli generated by this study are suitable for measuring speech recognition in Jordanian Arabic-speaking listeners.

BACKGROUND: Otosclerosis is a common cause of progressive hearing impairment that causes fixation of the stapes. Surgical intervention is the preferred treatment approach to ameliorate the conductive hearing loss associated with stapedial otosclerosis. However, given that it is a difficult and delicate procedure, the surgery may fail for a number of reasons. Therefore, it is very important to evaluate the success rate of the surgical approach used in each regional center. OBJECTIVE: To examine the effectiveness of stapedotomy in improving hearing sensitivity for otosclerotic patients at King Abdul Aziz University Hospital in Riyadh. DESIGN: Retrospective chart review with an analysis of pre- and postoperative surgical treatment. SETTING: Tertiary referral otolaryngology clinic. PATIENTS AND METHODS: All cases who underwent stapedotomy between 1997 and 2009 were retrospectively reviewed. Preoperative and postoperative audiometric assessments were conducted using conventional pure tone audiometry. Differences were analyzed by two-way repeated measures ANOVA. MAIN OUTCOME MEASURE(S): Pre- and postoperative pure tone thresholds for air and bone conduction. RESULT: Fifty-three patients underwent stapedotomy. Stapedotomy yielded significant improvements in mean (SD) postoperative air-conduction thresholds of about 18.7 (11.7) dB (P

Purpose: The aim of this work is to examine the efficacy of using computer-based training program (Rannan) as an intervention approach to enhance sound detection and discrimination in Arabic-speaking children with cochlear implants (CIs). Research Design: A prospective study comparing performance between two groups of children. Participants were divided into two equal groups that were matched in age and programming strategies. Group I received the traditional clinic-based therapy and group II received the same traditional therapy approach in addition to a computer-based program. Study Sample: A total of 26 children with CIs in the age range of 3–6.5 yr were recruited from King Abdulaziz University Hospital. Data Collection and Analysis: Listening Progress Profile and Infant–Toddler Meaningful Integration Scale were used preoperatively, and to compare performance between the two groups at 1-, 3-, 6-, and 12-mo after device-fitting. Data were subjected to mixed analysis of variance. Results: Both assessment tools (Listening Progress Profile and Infant–Toddler Meaningful Integration Scale) revealed that group II scored higher than group I. Conclusion: The study demonstrated that using computer-based training in addition to the traditional rehabilitation therapy can serve as a facilitative tool to enhance the benefit achieved from CI.

This report highlights research projects relevant to binaural and spatial hearing in adults and children. In the past decade we have made progress in understanding the impact of bilateral cochlear implants (BiCIs) on performance in adults and children. However, BiCI users typically do not perform as well as normal hearing (NH) listeners. In this article we describe the benefits from BiCIs compared with a single cochlear implant (CI), focusing on measures of spatial hearing and speech understanding in noise. We highlight the fact that in BiCI listening the devices in the two ears are not coordinated; thus binaural spatial cues that are available to NH listeners are not available to BiCI users. Through the use of research processors that carefully control the stimulus delivered to each electrode in each ear, we are able to preserve binaural cues and deliver them with fidelity to BiCI users. Results from those studies are discussed as well, with a focus on the effect of age at onset of deafness and plasticity of binaural sensitivity. Our work with children has expanded both in number of subjects tested and age range included. We have now tested dozens of children ranging in age from 2 to 14 yr. Our findings suggest that spatial hearing abilities emerge with bilateral experience. While we originally focused on studying performance in free field, where real world listening experiments are conducted, more recently we have begun to conduct studies under carefully controlled binaural stimulation conditions with children as well. We have also studied language acquisition and speech perception and production in young CI users. Finally, a running theme of this research program is the systematic investigation of the numerous factors that contribute to spatial and binaural hearing in BiCI users. By using CI simulations (with vocoders) and studying NH listeners under degraded listening conditions, we are able to tease apart limitations due to the hardware/software of the CI systems from limitations due to neural pathology.

Although the cochlear implant is already the world's most successful neural prosthesis, opportunities for further improvement abound. Promising areas of current research include work on improving the biological infrastructure in the implanted cochlea to optimize reception of cochlear implant stimulation and on designing the pattern of electrical stimulation to take maximal advantage of conditions in the implanted cochlea. In this review we summarize what is currently known about conditions in the cochlea of deaf, implanted humans and then review recent work from our animal laboratory investigating the effects of preserving or reinnervating tissues on psychophysical and electrophysiological measures of implant function. Additionally we review work from our human laboratory on optimizing the pattern of electrical stimulation to better utilize strengths in the cochlear infrastructure. Histological studies of human temporal bones from implant users and from people who would have been candidates for implants show a range of pathologic conditions including spiral ganglion cell counts ranging from approximately 2% to 92% of normal and partial hair cell survival in some cases. To duplicate these conditions in a guinea pig model, we use a variety of deafening and implantation procedures as well as post1-deafening therapies designed to protect neurons and/or regenerate neurites. Across populations of human patients, relationships between nerve survival and functional measures such as speech have been difficult to demonstrate, possibly due to the numerous subject variables that can affect implant function and the elapsed time between functional measures and postmortem histology. However, psychophysical studies across stimulation sites within individual human subjects suggest that biological conditions near the implanted electrodes contribute significantly to implant function, and this is supported by studies in animal models comparing histological findings to psychophysical and electrophysiological data. Results of these studies support the efforts to improve the biological infrastructure in the implanted ear and guide strategies which optimize stimulation patterns to match patient-specific conditions in the cochlea.

The possibility that "dead regions" or "spectral holes" can account for some differences in performance between bilateral cochlear implant (CI) users and normal-hearing listeners was explored. Using a 20-band noise-excited vocoder to simulate CI processing, this study examined effects of spectral holes on speech reception thresholds (SRTs) and spatial release from masking (SRM) in difficult listening conditions. Prior to processing, stimuli were convolved through head-related transfer-functions to provide listeners with free-field directional cues. Processed stimuli were presented over headphones under binaural or monaural (right ear) conditions. Using Greenwood's [(1990). J. Acoust. Soc. Am. 87, 2592-2605] frequency-position function and assuming a cochlear length of 35 mm, spectral holes were created for variable sizes (6 and 10 mm) and locations (base, middle, and apex). Results show that middle-frequency spectral holes were the most disruptive to SRTs, whereas high-frequency spectral holes were the most disruptive to SRM. Spectral holes generally reduced binaural advantages in difficult listening conditions. These results suggest the importance of measuring dead regions in CI users. It is possible that customized programming for bilateral CI processors based on knowledge about dead regions can enhance performance in adverse listening situations.

A cochlear implant vocoder was used to evaluate relative contributions of spectral and binaural temporal fine-structure cues to speech intelligibility. In Study I, stimuli were vocoded, and then convolved through head related transfer functions (HRTFs) to remove speech temporal fine structure but preserve the binaural temporal fine-structure cues. In Study II, the order of processing was reversed to remove both speech and binaural temporal fine-structure cues. Speech reception thresholds (SRTs) were measured adaptively in quiet, and with interfering speech, for unprocessed and vocoded speech (16, 8, and 4 frequency bands), under binaural or monaural (right-ear) conditions. Under binaural conditions, as the number of bands decreased, SRTs increased. With decreasing number of frequency bands, greater benefit from spatial separation of target and interferer was observed, especially in the 8-band condition. The present results demonstrate a strong role of the binaural cues in spectrally degraded speech, when the target and interfering speech are more likely to be confused. The nearly normal binaural benefits under present simulation conditions and the lack of order of processing effect further suggest that preservation of binaural cues is likely to improve performance in bilaterally implanted recipients.

To determine if cochlear implants recipients can be safely and effectively fitted with their sound processor one day after their implant surgery.All subjects were implanted with MED-EL Concerto cochlear implant. Subjects' electrode impedance levels, maximum comfortable levels, and threshold levels were measured one day after surgery and compared to measurements obtained one month post implantation using the non-parametric Wilcoxon signed-rank test.Twenty-nine participants in the age range of 1 to 42 years (average of 5 years).No adverse events were reported post-operatively. Measures after one day of surgery were significantly less than those measured one month post implantation.Early activation of the implant did not impact the healing process of the incision site, suggesting that one-day activation of the implant is feasible for some patients when medically possible. The evolution of the impedance and stimulation levels were consistent with that reported in previous studies, which indicates that early activation did not interfere with the physiological changes taking place after implantation.

Previous studies in our laboratory showed that temporal acuity as assessed by modulation detection thresholds (MDTs) varied across activation sites and that this site-to-site variability was subject specific. Using two 10-channel MAPs, the previous experiments showed that processor MAPs that had better across-site mean (ASM) MDTs yielded better speech recognition than MAPs with poorer ASM MDTs tested in the same subject. The current study extends our earlier work on developing more optimal-fitting strategies to test the feasibility of using a site-selection approach in the clinical domain. This study examined the hypothesis that revising the clinical speech processor MAP for cochlear implant (CI) recipients by turning off selected sites that have poorer temporal acuity and reallocating frequencies to the remaining electrodes would lead to improved speech recognition. Twelve CI recipients participated in the experiments. We found that site selection procedure based on MDTs in the presence of a masker resulted in improved performance on consonant recognition and recognition of sentences in noise. In contrast, vowel recognition was poorer with the experimental MAP than with the clinical MAP, possibly due to reduced spectral resolution when sites were removed from the experimental MAP. Overall, these results suggest a promising path for improving recipient outcomes using personalized processor-fitting strategies based on a psychophysical measure of temporal acuity.

The aim of this study was to identify across-site patterns of modulation detection thresholds (MDTs) in subjects with cochlear implants and to determine if removal of sites with the poorest MDTs from speech processor programs would result in improved speech recognition. Five hundred millisecond trains of symmetric-biphasic pulses were modulated sinusoidally at 10 Hz and presented at a rate of 900 pps using monopolar stimulation. Subjects were asked to discriminate a modulated pulse train from an unmodulated pulse train for all electrodes in quiet and in the presence of an interleaved unmodulated masker presented on the adjacent site. Across-site patterns of masked MDTs were then used to construct two 10-channel MAPs such that one MAP consisted of sites with the best masked MDTs and the other MAP consisted of sites with the worst masked MDTs. Subjects' speech recognition skills were compared when they used these two different MAPs. Results showed that MDTs were variable across sites and were elevated in the presence of a masker by various amounts across sites. Better speech recognition was observed when the processor MAP consisted of sites with best masked MDTs, suggesting that temporal modulation sensitivity has important contributions to speech recognition with a cochlear implant.

Gap detection threshold (GDT) is a commonly used measure of temporal acuity in cochlear-implant (CI) recipients. This measure, like other measures of temporal acuity, shows considerable variation across subjects and also varies across stimulation sites within subjects. The aims of this study were (1) to determine whether across-site variation in GDTs would be reduced or maintained with increased stimulation levels; (2) to determine whether across-site variation in GDTs at low stimulation levels was related to differences in loudness percepts at those same levels; and (3) to determine whether matching loudness levels could reduce across-site differences in GDTs. Thresholds and maximum comfortable loudness levels were measured in postlingually deaf adults using all available sites in their electrode arrays. All sites were then surveyed at 30% of the dynamic range (DR) to examine across-site variation. Two sites with the largest difference in GDTs were then selected and for those two sites GDTs were measured at multiple levels of the DR (10%, 30%, 50%, 70%, and 90%). Stimuli consisted of 500 ms trains of symmetric-biphasic pulses, 40 μs/phase, presented at a rate of 1000 pps using a monopolar (MP1+2) electrode configuration. To examine perceptual differences in loudness, the selected sites were loudness-matched at the same levels of the DR. Variations in GDTs and loudness patterns were observed across stimulation sites and across subjects. Variations in GDTs across sites tended to decrease with increasing stimulation levels. For the majority of the subjects, stimuli at a given level in %DR were perceived louder at sites with better GDTs than those presented at the same level in %DR at sites with poorer GDTs. These results suggest that loudness is a contributing factor to across-site variation in GDTs and that CI fittings based on more detailed loudness matching could reduce across-site variation and improve perceptual acuity.

This study introduces a new test (CRISP-Jr.) for measuring speech intelligibility and spatial release from masking (SRM) in young children ages 2.5–4 years. Study 1 examined whether thresholds, masking, and SRM obtained with a test designed for older children (CRISP) and CRISP-Jr. are comparable in 4 to 5-year-old children. Thresholds were measured for target speech in front, in quiet, and with a different-sex masker either in front or on the right. CRISP-Jr. yielded higher speech reception thresholds (SRTs) than CRISP, but the amount of masking and SRM did not differ across the tests. In study 2, CRISP-Jr. was extended to a group of 3-year-old children. Results showed that while SRTs were higher in the younger group, there were no age differences in masking and SRM. These findings indicate that children as young as 3 years old are able to use spatial cues in sound source segregation, which suggests that some of the auditory mechanisms that mediate this ability develop early in life. In addition, the findings suggest that measures of SRM in young children are not limited to a particular set of stimuli. These tests have potentially useful applications in clinical settings, where bilateral fittings of amplification devices are evaluated.

In humans with cochlear implants, functional measures show considerable variation from one stimulation site to another along the electrode array. Our research has demonstrated that (1) the across-site patterns of the functional data are stable over time but differ across subjects; and (2) the across-site patterns are measure specific. These observations are consistent with the hypotheses that implant performance at a given stimulation site is dependent on specific conditions near the site, and that the various functional measures do not all depend on the same conditions. However, we lack direct evidence as to the specific conditions leading to the site-specific differences in performance in humans. Studies in our guinea pig laboratory and elsewhere have demonstrated highly significant correlations between psychophysical or electrophysiological measures of implant function and anatomical measures of cochlear health. Furthermore, the correlated anatomical features differ across functional measures. Finally, some functional measures that are correlated with anatomical measures of cochlear health in animals are predictive of speech recognition ability in human implant users. The data support efforts to preserve and/or restore the health of the implanted cochlea. [This work was supported by NIH/NIDCD grants R01 DC010786, R01 DC010412, and P30 DC05188, and a contract from MED-EL.]

Table TABLE II. on page 4037 is incorrect. The wrong table was submitted during the review/revision process. The corresponding Fig. 7 and the text in the published paper are correct. The correct table is below. TABLE II. Percent correct scores for consonants and vowels. Mean and standard deviation for the 12 listeners are shown for each condition.